The assertion that the blue-greens (‘cyanobacteria’) are bacteria and not algae has led to alternative concepts for both of the latter terms. Bacteria is now often used to designate the prokaryote kingdom, that includes the blue-greens, while in other contexts it means specifically those prokaryotes that are not blue-greens. The term algae, on the other hand, has no biosystematic implications; it encompasses many phylogenetically independent lineages characterized by oxygen-evolving photosynthesis. The algal status of the blue-greens is therefore not compromised by their classification among the bacteria. Current lichenological terminology, however, reflects the view that the blue-greens are not algae, thereby diverging from the concept of algae employed in phycology. The purpose and utility of terms that group organisms according to structural, functional and ecological criteria are insufficiently appreciated. These concepts do not compete with phylogenetic/biosystematic classifications, but rather complement them.

Eight new species of Xanthoparmelia (Parmeliaceae) are described from eastern Australia: X. biloelensis Elix, X. fracticollis Elix, X. kosciuszkoensis Elix, X. nerrigensis Elix, X. paratasmanica Elix, X. rankinensis Elix, X. remanella Elix and X. stuartioides Elix. In addition, a further ten new state records of Xanthoparmelia are reported from eastern Australia.

The type material of Physciamagara Kremp., which is the type species of Seirophora Poelt (Teloschistaceae), is shown to be heterogeneous. It is a mixture of Teloschistesvillosus (Ach.) Norman and Ramalinamaciformis (Delile) Bory. Physciamagara Kremp. is typified on the T. villosus-part. Teloschistes species with multiseriate hairs, spores with short septa, thick and strongly conglutinated cortex hyphae with thick walls, lacking cilia or rhizines, and which have a mainly northern hemispheric distribution, are transferred to Seirophora. The following new combinations are made: Seirophora aurantiaca (R. Br.) Frödén, Seirophora austroarabica (Sipman) Frödén, Seirophora californica (Sipman) Frödén, Seirophora contortuplicata (Ach.) Frödén, Seirophora lacunosa (Rupr.) Frödén, Seirophora scorigena (Mont.) Frödén, Seirophora stenophylla (Tav.) Frödén, and Seirophora villosa (Ach.) Frödén.

The first molecular phylogenetic study on a range of Punctelia species is reported, focussing on specimens growing in the Iberian Peninsula. Material of seven species was included in the analysis. Forty sequences were generated from nuITS and mtSSU rDNA in 20 specimens, and the resultant majority rule consensus tree from the combined analyses shows four major clades. Punctelia ulophylla is confirmed as a distinct species, P. reddenda is basal to P. borreri, and P. perreticulata groups with P. subrudecta. Samples identified as P. rudecta from the Canary Islands and China occupy different basal positions; the complex merits further study. Punctelia borreri and P. subrudecta are mainly coastal in the Iberian Peninsula, but are now reported from the central plateau for the first time; newly colonizing thalli have been found in a park in Madrid which is regularly spray-watered and where sulphur dioxide levels have fallen over the last two decades.

An inventory of foliicolous lichens in Mexican lowland and montane rainforest revealed a total of 288 species, 238 of which are new records for the country, raising the number of reported lichen species to c. 1800. Among the new records, there are 29 recently described species and four new records for the Neotropics and the Americas, while five taxa are for the first time reported for Central America. The 293 species now known from Mexico comprise nearly two-thirds pantropical to cosmopolitan or intercontinentally distributed taxa, whereas little more than one-third are Neotropical or American, and only 6% are potentially endemic to the country. A comparison with other lowland and montane rainforest sites in Guatemala, Costa Rica and Ecuador shows that on average lowland sites have twice as many species as montane sites. Also, the differentiation in species composition between lowland and montane sites within the same region is more pronounced (63–75% similarity) than that between adjacent regions (96–99% similarity for lowland sites and 83–87% similarity for montane sites). This means that altitudinal preferences affect species composition more strongly than geographical differentiation. The latter is a function of distance, however, while Mexican and Guatemalan lowland (montane) sites share 96% (83%) of the species, these values drop to 74% (72%) when comparing Mexico with Ecuador. Nevertheless, overall floristic similarity is very high, with the lowest value of 54% shared species found between Mexican lowland and Costa Rican montane forest.

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.

Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.

Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

While studying the taxonomy of the non-yellow species of Rhizocarpon DC., with hyaline and muriform ascospores, in the Nordic countries (Ihlen 2004), some specimens of Rhizocarpon from the Svalbard archipelago were also examined. Among this material, we discovered six specimens of Rhizocarpon anaperum (Vain.) Vain. that had been labelled “R. obscuratum”. As R. anaperum is not listed in the recent checklist from Svalbard (Elvebakk & Hertel 1996) or, to our knowledge, in any other paper dealing with the lichen flora of Svalbard, it is here reported new to this archipelago.

Jørgensen & James (1983) in their detailed study of the Leptogium azureum group in western Europe, pointed out that L. azureum (Swartz) Mont. was absent from Europe and that most of the European material so named belongs to L. cochleatum (Dicks.) P. M. Jørg. & P. James. Although both species show some morphological similarity, they also show a great number of differences. Leptogium cochleatum develops a darker and thicker thallus than L. azureum, with a finely striate upper surface, a different arrangement of the photobiont in the thallus, apothecia with persistent±wrinkled margins, proper euparaplectenchymatous exciples, the presence of paraplectenchymatous tissue at the base of apothecia and muriform ascospores which are larger than in L. azureum. For a summary of the most important characters distinguishing these two species see Jørgensen & James (1983). Leptogium valdivianum M. Lindström, a species from cool temperate South America, has also been confused with L. azureum, however, it can be distinguished by its distinctly thicker and dark leaden grey­blue thallus, apothecia with persistent thalline margins and its larger and broader distinctly muriform ascospores (Galloway & Jørgensen 1995; Lindström 1996).